prooftrans: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/prooftrans - from package: prover9

You may install the required package with command apt-get install {package}

Error in other languages:
prooftrans: bevel nie gevind nie
prooftrans: comandă negăsită
prooftrans: comando não encontrado
prooftrans: commande introuvable
prooftrans: command not found
prooftrans: käsku ei ole
prooftrans: không tìm thấy lệnh
prooftrans: komanda nerasta
prooftrans: Kommando nicht gefunden.
prooftrans: kommandot finns inte
prooftrans: komut yok
prooftrans: nie znaleziono polecenia
prooftrans: níor aimsíodh an t-ordú
prooftrans: no se encontró la orden
prooftrans: no s'ha trobat l'ordre
prooftrans: opdracht niet gevonden
prooftrans: parancs nem található
prooftrans: perintah tidak ditemukan
prooftrans: príkaz nenájdený
prooftrans: příkaz nenalezen
prooftrans: команда не найдена
prooftrans: командата не е открита
prooftrans: 命令找不到
prooftrans: コマンドが見つかりません